Calendar Adjustment Day 2017 is on Friday, September 1, 2017: How did we start using the calendar and knew when to start.?

Friday, September 1, 2017 is Calendar Adjustment Day 2017. September 02) Today we're celebrating . . . Calendar Adjustment ... Calendar Adjustment Day

Calendar Adjustment Day

Following a British Calendar Act of 1751, Britain adopted the Gregorian Calendar in 1752. However, the present Julian calendar system needed these to drop eleven days to be able to sync themselves using the suggested Gregorian Calendar. So, around the evening of second September 1752, the populace of england and it is American colonies visited sleep and awoke the following morning to 14th September 1752.The move can also be accountable for New Year’s Day being celebrated on first The month of january, as before this it absolutely was celebrated on 26th March.Consequently of Calendar Adjustment Day, there is rioting around the roads by individuals who felt scammed, and required the eleven days back!

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How did we start using the calendar and knew when to start.?

History of the Calendar

The purpose of the calendar is to reckon past or future time, to show how many days until a certain event takes place—the harvest or a religious festival—or how long since something important happened. The earliest calendars must have been strongly influenced by the geographical location of the people who made them. In colder countries, the concept of the year was determined by the seasons, specifically by the end of winter. But in warmer countries, where the seasons are less pronounced, the Moon became the basic unit for time reckoning; an old Jewish book says that “the Moon was created for the counting of the days.”

Most of the oldest calendars were lunar calendars, based on the time interval from one new moon to the next—a so-called lunation. But even in a warm climate there are annual events that pay no attention to the phases of the Moon. In some areas it was a rainy season; in Egypt it was the annual flooding of the Nile River. The calendar had to account for these yearly events as well.

The Egyptian Calendar

The ancient Egyptians used a calendar with 12 months of 30 days each, for a total of 360 days per year. About 4000 B.C. they added five extra days at the end of every year to bring it more into line with the solar year.1 These five days became a festival because it was thought to be unlucky to work during that time.

The Egyptians had calculated that the solar year was actually closer to 3651/4 days, but instead of having a single leap day every four years to account for the fractional day (the way we do now), they let the one-quarter day accumulate. After 1,460 solar years, or four periods of 365 years, 1,461 Egyptian years had passed. This means that as the years passed, the Egyptian months fell out of sync with the seasons, so that the summer months eventually fell during winter. Only once every 1,460 years did their calendar year coincide precisely with the solar year.

In addition to the civic calendar, the Egyptians also had a religious calendar that was based on the 291/2-day lunar cycle and was more closely linked with agricultural cycles and the movements of the stars.

1. The correct figures are lunation: 29 d, 12 h, 44 min, 2.8 sec (29.530585 d); solar year: 365 d, 5 h, 48 min, 46 sec (365.242216 d); 12 lunations: 354 d, 8 h, 48 min, 34 sec (354.3671 d).

Lunar Calendars

During antiquity the lunar calendar that best approximated a solar-year calendar was based on a 19-year period, with 7 of these 19 years having 13 months. In all, the period contained 235 months. Still using the lunation value of 291/2 days, this made a total of 6,9321/2 days, while 19 solar years added up to 6,939.7 days, a difference of just one week per period and about five weeks per century.

Even the 19-year period required adjustment, but it became the basis of the calendars of the ancient Chinese, Babylonians, Greeks, and Jews. This same calendar was also used by the Arabs, but Muhammad later forbade shifting from 12 months to 13 months, so that the Islamic calendar now has a lunar year of about 354 days. As a result, the months of the Islamic calendar, as well as the Islamic religious festivals, migrate through all the seasons of the year.

The Roman Calendar

When Rome emerged as a world power, the difficulties of making a calendar were well known, but the Romans complicated their lives because of their superstition that even numbers were unlucky. Hence their months were 29 or 31 days long, with the exception of February, which had 28 days. However, four months of 31 days, seven months of 29 days, and one month of 28 days added up to only 355 days. Therefore the Romans invented an extra month called Mercedonius of 22 or 23 days. It was added every second year.

Even with Mercedonius, the Roman calendar eventually became so far off that Julius Caesar, advised by the astronomer Sosigenes, ordered a sweeping reform. 46 B.C. was made 445 days long by imperial decree, bringing the calendar back in step with the seasons. Then the solar year (with the value of 365 days and 6 hours) was made the basis of the calendar. The months were 30 or 31 days in length, and to take care of the 6 hours, every fourth year was made a 366-day year. Moreover, Caesar decreed the year began with the first of January, not with the vernal equinox in late March.

This calendar was named the Julian calendar, after Julius Caesar, and it continues to be used by Eastern Orthodox churches for holiday calculations to this day. However, despite the correction, the Julian calendar is still 111/2 minutes longer than the actual solar year, and after a number of centuries, even 111/2 minutes adds up.

The Gregorian Reform

By the 15th century the Julian calendar had drifted behind the solar calendar by about a week, so that the vernal equinox was falling around March 12 instead of around March 20. Pope Sixtus IV (who reigned from 1471 to 1484) decided that another reform was needed and called the Ge

Who owns the Gregorian Calendar and what authority regulates it?

Who owns the Gregorian Calendar and what authority regulates it?

The Gregorian calendar doesn't need regulating. It is merely a set of rules to fix the lengths of the months, so that the season are more-or-less fixed in relation to the height of the Sun in the sky. Occasionally, it deviates from the true (Tropical or Solar) year because of fluctuations in the solar system of planets and that needs a correction that everyone applies. The Bureau International de l'Heure (BIH) or the International Time Bureau, at the Paris Observatory, was the international bureau responsible for combining different measurements of Universal Time until 1987. The responsibilities of the Bureau were taken over by the International Bureau of Weights and Measures (BIPM) and the International Earth Rotation and Reference Systems Service (IERS) which is located at Sèvres, France.

All calendars are wrong, in the sense that the orbit is not fixed, being subject to various fluctuations over a year, a decade and the centuries. At the moment, the length of the year averages 365.2425 rotations of the Earth. The Gregorian calendar is not perfectly accurate either. It is in error by about 27 seconds per year and this needs to be corrected periodically, in addition to the Leap Year correction.

In fact, the Gregorian should be named after the German astronomer Christopher Clavius (1537-1612), who worked out the procedures for stabilising that calendar. Other calendars are named after people. There is the earlier Julian, named after Julius Caesar. Also, the Khayyam, named after the Persian polymath (1048-1131). And there is the calendar of Johann Heinrich von Mädler (1794-1874) which was offered to the Tsar of Russia in 1856, but rejected.

The Gregorian calendar is not the only one in regular use but others have special applications. Astronomers need to define a year differently, so the Gregorian is sometimes not the most useful. Also, there are regional calendars in use for the purpose of determining religious dates and festivals, which are almost always lunar-based. One is the North African Berber Calendar and another is the Hindu Calendar. In many countries, regional calendars are in daily use and their timings are under the control of priests or other authorities of the appropriate religion. Generally, they vary in annual length from 354 to 360 days, and therefore need regular adjustment, again by the priestly authorities.

There is a very interesting graph at the Wiki below: it shows the way the Gregorian calendar averages the "correct" length of the year by its Leap Year corrections, based on the Summer Solstice.


Who invented the 365 day year?

Who invented the 365 day year?

The Babylonians created a calendar of 12 months of 30 days each and then added 5 festival days to get the 365 days in a year. The Babylonians are credited with inventing the 12 constellations of the zodiac as a way of tracking the sun as it appeared to spend approximately 30 days or a month in each constellation.

Caesar's astronomer, Sosigenes, developed the Julian calendar based on the fact that it takes the earth 365 days, 5 hours, 48 minutes and 46 seconds to revolve around the sun. This time was abbreviated to 365 1/4 days, and a calendar year was defined as 365 days, with one "leap day" added every four years to compensate for the lost quarter day.

Julius Caesar, who established the leap year as part of his Julian calendar in 45 B.C.

As time ticked on, people began noticing the flaws of the Julian calendar. In 1582, Pope Gregory XII noticed that the spring equinox---when day and night are of equal length---fell upon March 11 instead of March 21.

The pope fixed the problem by erasing 10 days, declaring that the day following Oct. 4, 1582 would be known as Oct. 15, 1583. To make the calendar more sun-accurate than Caesar's, Pope Gregory XII pulled out his abacus and calculated the following leap year restrictions (I'd advise a swig of coffee here): If the first year of a century is divisible by 400, it is a leap year; if it's not, then that year isn't a leap year.

The pope's mathematical modification knocked out leap years in 1800 and 1900, but in 2000 we'll have another one, because 2000 divides evenly into 400. Unless it's a centennial year, you can determine a leap year without looking at a calendar by dividing it by four. It if divides evenly, with no reaminder, it's a leap year. If you're lazy, like me, you can also flip through a calendar in search of February 29.

Pope Gregory XII's calendar, known as the Gregorian calendar, now hangs on most of our walls. It wasn't as popular when it was first developed, though.

Although most Roman Catholic countries adopted it at once because it recalibrated the beginning of spring and restored Easter to its proper time, Protestant countries didn't make the change for 200 years. England resisted the switch until 1752, and the loss of 11 days caused by the date adjustment spurred riots in the streets.

Russia didn't accept the Gregorian calendar until 1918, which means that when the U.S. purchased Alaska in 1867, 11 days were lost in the transition from the Julian calendar.

Leap years are also significant for Alaskans because summer solstice occurs about 18 hours earlier in a leap year. Since we have an extra day this year, summer solstice---when the earth tilts Alaska nearest the sun---happens at 5:24 p.m. on June 20th instead of on the traditional June 21.

I'll try to keep that sunny thought in mind next Monday morning.

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